


Kinktober 2019: Kinknado

by Vexatious



Category: Undertale (Video Game)
Genre: Alternate Universe - Dreamtale (Undertale), Alternate Universe - Fellswap Gold (Undertale), Alternate Universe - Swapfell (Undertale), Alternate Universe - Underfell (Undertale), Alternate Universe - Underlust (Undertale), Alternate Universe - Underswap (Undertale), Alternate Universe - Yanderetale (Undertale), Begging, Biting, Blow Jobs, Bondage, Breathplay, Breeding, Bukkake, Come Inflation, Come Swallowing, Creampie, Deepthroating, Degradation, Dirty Talk, Domesticity, Ecto-Genitalia (Undertale), Ecto-Penis (Undertale), Ecto-Tentacles (Undertale), Ecto-Tongue (Undertale), Ecto-Vagina (Undertale), Exhibitionism, Face-Fucking, Gags, Gentle Dom, Glory Hole, Grinding, Horrortale Sans (Undertale), Jealousy, Kidnapping, Knotting, Masturbation, Mating Cycles/In Heat, Mild Painplay, Multi, Nightmare Sans - Freeform, Nipple Play, Oral Sex, Possessive Behavior, Praise Kink, Public Masturbation, Rough Oral Sex, Rough Sex, Shower Sex, Size Difference, Skeleton Pregnancy (Undertale), Socket Penetration, Spanking, Spitroasting, Swapfell Papyrus (Undertale), Swapfell Sans (Undertale), Threesome, Underfell Papyrus (Undertale), Underfell Sans (Undertale), Underswap Papyrus (Undertale), Underswap Sans (Undertale), Vaginal Fingering, gaping, phallic gags, skelepreg, upskirt sex
Language: English
Status: In-Progress
Published: 2019-09-30
Updated: 2020-09-12
Packaged: 2020-11-08 09:11:31
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 10
Words: 10,093
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20832977
Author URL: https://archiveofourown.org/users/Vexatious/pseuds/Vexatious
Summary: Each chapter will have a list of kinks as well as the pairing for that chapter. Tags for the collection will change as new chapters are added. Enjoy!





	1. Introduction

The writer sank into her desk chair and opened a blank Google document. Her obnoxious roommate, Jerry, was thankfully absent, and she finally had a few moments of peace and quiet to start writing her Kinktober prompts. Unfortunately, this year provided yet another influx of shudder-inducing Jerry requests.

The writer didn’t understand how anyone could fetishize a potato with legs-

“We’re out of cake batter ice cream,” said a monotone voice from the doorway of the room, accompanied by the frantic tapping of phone keys sending a text. The potato with legs had arrived as if summoned by the mere description of his strangely bulbous body. 

_ Jerry. _

“I just bought that ice cream!” _For myself_, added the writer silently, clenching her teeth against any further remarks that might encourage her unwelcome guest to linger. Jerry needed no encouragement however.

“Yeah, I accidentally knocked it off the counter. You should probably clean that up before we get ants. I hate ants.” 

_Don’t ask why it was on the counter. Don’t point out that he should be the one cleaning up the things that he spills_, the writer chanted mentally, waiting for Jerry to get bored enough to wander off and bother someone else. No such luck.

_Tap, tap, tap_. The sound of relentless texting grew closer. Or maybe it was the sound of Jerry’s ridiculous footwear? He couldn’t be bothered to wear pants, but he never took off the heels, even in the house. Did he wear them in the shower? The writer didn’t want to think about it.

“What’cha doin’?” asked Jerry, already scrutinizing the computer screen while standing far too close and leaning over the writer’s shoulder at that uncomfortable proximity. “Potato? Rude.”

Because calling someone a potato with legs is obviously far more rude than, for example, eating the ice cream that someone bought for themselves, spilling it, then telling them to clean it up. Still, while Jerry was here disregarding personal space, the writer could ask him a question that had been weighing on her mind since he’d crashed last year’s Kinktober.

“Jerry?” 

The monster had already turned back to his phone, finger-like appendages flying over the keys. At least he had the decency to acknowledge the writer with a noncommittal grunt, so she went ahead and asked her question: “What part of you, exactly, is the, uh, genitals?” It seemed like an odd question, but Jerry was famously well-endowed and never wore pants. Inquiring minds wanted to know… only so they could write accurate Jerry Kinktober prompts, of course.

“What part of me is the genitals?” Jerry echoed before saying the three words that would haunt the writer to her grave.

“All of me.”

Jerry didn’t need to gyrate while gesturing at himself, but he did, and the words played over and over in her head.

All of me.

_ All. _

_ Of. _

_ Me. _


	2. Day One: BlackBlood (Glory Hole, Bukkake, Sexual Frustration)

**Summary for the Chapter:**

> Pairing: HT!Sans x SF!Sans (BlackBlood)
> 
> Featured Kinks: Glory Hole, Bukkake, Sexual Frustration (mild)
> 
> Additional Warnings: Kidnapping, degradation (mild), cum swallowing, cum inflation (mild)

Blood despised Fell universe skeletons and their holier than thou attitudes. Each and every one of them lamented about his (or occasionally her) kill or be killed lifestyle, but none of them had the dustthirsty edge of a monster who truly lived by that mantra. None of them had holes in their skulls or eyelights grown large and ragged from overused and chronically depleted magic. None of them had the oversized stature or thick bones of a skeleton who fought to survive like he did.

Now a scrawny little skeleton with a scar over one socket stood in front of him, imperiously proclaiming himself to be the Captain of the Swapfell universe’s Royal Guard and extolling the hardships of a kill or be killed existence despite the fact that Blood easily dwarfed him. Blood had had enough, and an itchy tingle of sexual frustration in his pelvis gave him an idea of just how this arrogant skeleton could be put to good use.

Blood swung the haft of his massive cleaver. For a Royal Guard Captain in a supposedly cutthroat universe, the other skeleton had surprisingly slow reflexes. He crumpled to the ground like a boney ragdoll. _Swap-verse Sanses couldn’t teleport worth a damn_, Blood chuckled to himself, tossing the unconscious skeleton over his shoulder and teleporting to a favorite haunt of his.

* * *

Blackberry, proud Captain of the Royal Guard, awoke in a cramped prison with a splitting headache and no memory of how he arrived there. Exploration of his surroundings only took a few seconds. The cell, dimly lit by the glow of his magic, was little more than a narrow box with a low ceiling, barely any room to shift positions, and a conspicuous hole in the wall. Hesitantly, Black attempted to peer out of the hole only to have his socket nearly impaled by a dark red cock entering the hole from what he assumed was a much larger room outside.

The confined space provided no room for retreat, so Blackberry could only turn his face to the side. The cock rubbed against his cheek, smearing warm, sticky pre-cum across his cheekbone. He scowled. How dare this impudent monster imprison him and expect him to perform at this ridiculous gloryhole? The dark red shaft continued to prod at his face. He considered biting it, but as soon as he turned towards it, his mouth began to water.

It had been quite some time since Black last indulged himself in sexual activities, and the sight of such a thick, throbbing cock, right there for the taking, made him rub his femurs together against the ache starting low in his pelvic inlet. The gloryhole cell smelled like sweat and sex, and Blackberry’s body responded, flooding him with desire. When another bead of pre-cum gathered at the tip of the waiting cock, he lapped it up then opened his mouth to guide the cock inside.

Black barely had time to swallow the first hot load when another cock thrust its way into the gloryhole. Black licked and sucked each new cock noisily, saliva and cum running down his chin as he gulped down load after load of cum until he lost count of his conquests. Soon his stomach bulged from the influx of magic, and after an exquisitely knotted cock emptied itself deep in his throat, he realized that he couldn’t possibly hold any more.

Black thumped his fist against the wall of the cell, signalling that he’d had enough, and to his mild surprise, the side of the apparatus promptly opened up, revealing an opulently decorated room filled with chaise lounges where monsters of all types and sizes waited their turns to use gloryholes similar to the one he’d just vacated. Lust verses were lavish playgrounds of sexual release where the denizens rarely asked questions. None of the occupants of the room batted whatever passed for an eyelash at Blackberry or his captor.

With a groan, Black crawled out of the gloryhole cage on his hands and knees. As soon as he fully emerged onto the carpet, he coughed up a bit of the cum he’d just swallowed, wiping it away from the corner of his mouth with one gloved hand.

“Ya shouldn’t be wastin’ perfectly good cum like that,” growled a deep voice. Black lifted his eyelights to take in the speaker- the skeleton he’d met while on patrol in Snowdin Forest! The thick-boned skeleton monster leered down at him from an impressive height, but Black’s mind, clouded by lust, couldn’t tear itself away from the rock hard cock in the skeleton’s hand. Stars, he wanted it so badly. He reached for it.

The skeleton with the jagged hole marring his skull pulled away with a teasing tsk-tsk sound. “I invited all my friends here with the promise that you’d suck ‘em off. I’d hate to disappoint ‘em, so get on yer knees and form some titties for us like a good little slut,” the red-eyed skeleton rumbled.

Normally, Blackberry hated being given orders or referred to without the respect due to him, but his recent exploits at the gloryhole left him sex-drunk and desperate for more: more stimulation, more degradation, more cum. He knelt, and summoned two soft round breasts, tilting them up for the other skeleton’s viewing pleasure.

* * *

With a few rapid strokes of his cock, Blood spurted thick ropes of hot cum right onto Black’s waiting face. Some of it even got in the smaller skeleton’s eyesocket, but the twerp actually moaned from it! With wicked low laughter, Blood’s friends stepped forward, cocks in hand and began to pump themselves to completion. 

Sticky strands of cum rained down on Black’s upturned face and breasts, and he took all of it with hazy eyelights and a protruding tongue, begging for more in a lewd and desperate voice. Once Blood and his friends were spent and Black laid on the carpet, pale bones and translucent ecto covered in various colors of cum, a skeleton with a blue and red eyelight spoke up.

“So what’re we gonna do with ‘im now?” The skeleton asked.

Blood growled. “What do ya mean ‘we’? I found ‘im. This cum hungry little slut is mine!”

Black didn’t argue.

He wanted more, and he’d do whatever it took to get it.


	3. Day Two: Nightmare x US!Sans (Soft Dom/Coaching, Painplay)

**Summary for the Chapter:**

> Pairing: Nightmare x US!Sans
> 
> Featured Kinks: Soft Dom/Coaching, Painplay 
> 
> Additional Warnings: Bondage, fingering, tentacles, object insertion

By day, they kept up appearances. The Sans from Underswap, known as Blueberry or Blue, faithfully served as a member of the Star Sanses, upholding peace and order and defending the multiverse from monsters like Error and Nightmare. Nightmare, the embodiment of negative emotions, hunted his brother across the multiverse and spread negativity wherever he went. By night? Well, that was a different story.

* * *

Blue surveyed his handiwork, hands on his hipbones and a proud smile playing across his innocent-looking face. Nightmare sat propped up on the bed, wrists securely cuffed to the top rail of the bed frame. Nightmare, bane of the Star Sanses, was at Blue’s mercy, but justice could not have been further from Blue’s mind. His nemesis didn’t wear any clothing, and Blue had already stripped down to a soft pair of workout pants to begin a session that was more instruction than interrogation.

“The safeword is ‘Froggit,’” Blue said solemnly, inciting Nightmare to lunge forward as far as his restraints would allow.

“I don’t need a fucking safeword,” Nightmare snapped. “I want you to hurt me.” Blue ignored the outburst.

“No safeword, no painplay.” Blue climbed onto the bed and seated himself just out of Nightmare’s reach. “Now summon your tentacles so we can get started.”

Four thick, dripping tentacles sprang from Nightmare’s back then froze midair, awaiting Blue’s next command. Blue leaned forward to inspect them, admiring their girth and tapered shape before continuing his instructions.

“Use two of the tentacles to spread your pussy open for me. Yeah, just like that,” Blue’s voice lowered to a seductive purr. “So wet already? I love it.” Unlike the monster they belonged to, Nightmare’s pussy folds were soft and inviting.

The inner folds of Nightmare’s pussy glistened with arousal from being tied up and ordered around by Blue. Nothing turned him on quite like relinquishing control… except for Blue’s cock when Blue wrecked him from behind. Thoughts of the Underswap Sans slapping his ass while thrusting into him, perhaps while tugging on a leash attached to a collar around his neck, nearly caused Nightmare to miss Blue’s next words.

“Now I want you to rub your clit like this,” Blue scooted forward to demonstrate. Using his thumb, he pressed against Nightmare’s clit and slowly rubbed the sensitive nub in a circular motion. Nightmare hissed at the sudden, intense pleasure of Blue’s touch, but Blue pulled away far too soon for his liking. Nightmare replaced the motion of Blue’s absent thumb with a tentacle, and his pussy fluttered with desire for something to fill it.

“Mmm, that’s right. You’re doing so well… so obedient,” Blue whispered huskily, a haze of lust overtaking the bright blue eyelights in his half-lidded sockets. “I think I’ll reward you by getting you ready myself before we start our little game.” Nightmare shivered in anticipation. Blue’s innocent appearance hid an extremely sexual personality that few others had the opportunity to see, much to their own detriment.

Blue slipped two of his phalanges into his mouth and sucked on them until they were slick with his saliva, never taking his eyes off of Nightmare’s exposed pussy. He couldn’t wait to start playing with it. Nightmare made such beautiful noises when Blue fingered or fucked him. Blue suddenly found himself breathing heavily, craving the sensation of that hot, wet hole clamping down around him, but he prided himself on control. They’d only just gotten started, and Blue rather enjoyed the delayed gratification of doing things properly. Only fools rushed in.

Even lubricated with saliva and Nightmare’s own arousal, Blue’s phalanges barely fit into the tight little fuckhole, and the goopy skeleton’s cries of pleasure were undercut by a groan from Blue. The walls of Nightmare’s cunt sucked Blue’s fingers in greedily, and he worked them in and out until Nightmare’s abundant slick began to flow down his hand. Nightmare bucked his hips reflexively against the stimulation, and Blue forced himself to stop. He lifted his phalanges to his mouth and licked Nightmare’s juices off of them seductively. 

Nightmare struggled against his bonds, straining his pelvis to be closer to Blue, momentarily forgetting that the purpose of this session was painplay. Blue reminded him by summoning a bone attack and twirling it in his arousal stained fingers. Recognition and hunger shone in Nightmare’s eyelights.

“Time for the main event,” Blue announced. The slender bone began to glow orange. “Better keep moving,” he teased, slipping the makeshift sex toy into Nightmare’s eager cunt. Nightmare’s back arched and his hips jerked, thrusting himself against the bone attack over and over, desperately seeking relief from the yawning maw of need deep in his core. Something was missing though… but not for long.

Without warning the orange bone attack turned blue, and Nightmare’s movements caused twin jolts of pleasure and pain to shoot straight up his spine. His toes curled, his skull fell back onto the pillow, and his hands scrabbled at the bed sheets. Every movement set him on fire with pain that only heightened the pleasure of the bone sliding in and out of him, dragging against his sensitive walls.

Nightmare’s bucking hips juddered to a stop, and the slime-coated skeleton panted, recuperating from the intensity of the experience. A smile crept across Blue’s features, and the bone changed back to orange, causing Nightmare to go suddenly rigid as hot fluids gushed from his pussy around the bone attack. Blue didn’t let up after the first orgasm, but he did monitor the strength of his attacks carefully and watch Nightmare’s facial expressions and body language, not trusting the other monster to use the safeword he’d suggested. Besides, the sight of Nightmare in such a compromising position sent a tantalizing warmth into his own magic.

Throbbing and swollen with the fresh influx of magic, Blue’s cock demanded some of his attention as well, and he shoved his pants down to reveal the thick, aching shaft. Keeping the color changes of the bone attacks random to maximum Nightmare’s responses, Blue started to stroke the length of his cock, leisurely at first, then faster and faster as he watched Nightmare writhe and scream. His formidable nemesis looked so fucking sexy coming undone on the bed before him.

As orgasm after orgasm wracked Nightmare’s body, Blue added several hot loads of his cum to the sticky goo already coating Nightmare’s bones. “You look so beautiful like this,” he purred at Nightmare without slowing his pace at all.

* * *

If their clandestine tryst made things a bit awkward between them when they clashed in battle, both Blue and Nightmare considered the effort of hiding their mutual arousal to be well worth the trouble.


	4. Day Three: Polyruses (Papcest) (Breastplay/Nippleplay, Breeding, Phallic Gags, Shower)

**Summary for the Chapter:**

> Pairing: UT!Papyrus x US!Papyrus x UF!Papyrus x SF!Papyrus (Polyruses)
> 
> Featured Kinks: Breastplay/Nippleplay, Breeding, Phallic Gags, Shower
> 
> Additional Warnings: Skelepreg (mention), threesome, extremely late, a bit wordy, not much shower kink

Edge had babies on the brain lately. He found himself watching videos of babies on the internet, cooing over how adorable baby clothes were, and occasionally imagining himself with a gently curved stomach and a soulling (or two!) nestled safely inside. The more he thought about it, the more he wanted it. The decision was made; Edge wanted to bear a child.

All he needed to do now was broach the subject with his boyfriends… all three of them. How could he decide which one should father the soulling? He loved them all equally, and all three of them would be good candidates for breeding. Maybe they could work something out as a foursome…?

Edge broached the subject over a hearty breakfast prepared by Papyrus. Honey and Russ chowed down, but Edge pushed his food around on his plate for a few moments before tentatively saying: “I think… that I want to have a baby.”

After a split second of stunned silence, Papyrus, Honey, and Russ all spoke at once, saying the exact same words in perfect unison: “With me?”

Edge couldn’t hold back an affectionate chuckle. He loved these other skeletons with all of his SOUL; he could never choose between them! “I thought maybe… we could all try to make a baby together?” he suggested hesitantly. Sure, the four of them shared a very fulfilling polyamorous relationship, but Edge wasn’t sure how the other skeletons would feel about breeding him together. The four of them shared similar physical traits; it would be difficult if not impossible to know whose magic truly sired the child… just as Edge intended.

“May we have a moment to discuss it?” Papyrus asked politely, laying a slim hand on Honey and Russ’s shoulders. Honey appeared to be stunned and thoughtful, but Russ looked like he might jump across the table and tackle Edge to the kitchen floor to breed him then and there. None of them had refused or shown signs of disgust thankfully, and Edge thought discussing it sounded like a good idea. Having a child wasn’t something to take lightly.

“Take your time talking it over,” Edge offered with a loving smile to each of his boyfriends, so alike in appearance yet so different in personality, “I’m going upstairs to shower.” 

Edge had barely vanished through the kitchen door before Honey and Russ shared a mischievous look and dashed off after him. Chuckling to himself, Papyrus gave the breakfast dishes a quick rinse before following after them. Someone had to keep things tidy if they were planning to welcome a babybones into the world!

Meanwhile, Honey and Russ cornered Edge in the bathroom, enthusiastically helping him undress. Their own clothing haphazardly littered the stairway, another chore for Papyrus before he joined them. Honey turned on the hot water while Russ nuzzled their lover’s neck, and as steam began to rise from the cool surface of the bathtub, Honey turned his attention to Edge’s pelvis. 

Russ nibbled vertebrae while Honey’s agile tongue curled around Edge’s pubic symphysis. 

Dark red magic pooled low in Edge’s pelvis, taking on the shape of plump pussy lips with an already swollen clit just aching to be touched. Two small round breasts appeared on Edge’s ribcage, much to Russ’ delight. Their lover wore his feminine form with such grace and beauty that it almost seemed a shame to ravage him. Not that Honey or Russ ever let shame stop them.

A proverbial throat cleared from the bathroom doorway, momentarily distracting the three skeletons from their foreplay. Papyrus stood there with one hand on his hip. In the other hand he held a special phallic gag that could be infused with magic to deliver the pleasure of oral stimulation to one or more monsters whose magic infused it- a favorite toy of the polyamorous quartet.

“You’re wasting all of the hot water,” Papyrus chided gently. He tossed the phallic gag to Edge, who caught it easily. Edge held it up, raising one brow bone in a silent question. “That will keep us all primed to perform whenever we aren’t bottomed out in your silky sweet pussy,” he explained, “and without wasting even a drop of precious cum.” The three other skeletons nodded their approval. “It looks a bit crowded in here though, so I’ll await my turn in the bedroom.”

The door closed behind Papyrus with an appropriately perk click sound, and huge lecherous grins spread across Russ and Honey’s faces. Edge opened his mouth wide, letting his tongue protrude slightly to invite in the gag that shimmered with the magic of three skeletons. Once Honey had affixed the straps to hold the gag in place in Edge’s warm, wet mouth, Russ offered him a hand to help him into the shower… and then the fun began.

Russ lifted Edge by the femurs, angling him perfectly for penetration and graciously allowing Honey to go first, though he had ulterior motives. Lubed by the hot water and rock hard from Edge’s tongue stroking the phallic gag, Honey slid easily between Edge’s silken folds and deep into his hungry pussy. Edge moaned against the gag, causing Russ’ erection to throb against his coccyx, leaving a sticky bead of precum that the cascade of hot water quickly erased.

Honey gripped Edge’s pelvis as he began to thrust, relieving Russ from holding him up and allowing Russ’ hands to explore elsewhere, just as he had planned. Russ loved it when Edge formed tits; they were always perfect small handfuls with extremely sensitive nipples. Russ caught those nipples now between his phalanges and rolled them. If Edge had been standing, his legs would’ve gone weak from pleasure.

Russ nuzzled Edge’s scapula, phalanges deftly massaging Edge’s breasts, imagining them full with milk for their babybones. He closed his eyes and sighed. Having a babybones with his lovers would be the only thing in this world that could beat having sex with his lovers. He couldn’t wait to fill Edge with his cum and breed him properly. If only Honey would hurry up…

The moment Honey’s thrusts stuttered to a halt and his cum poured into Edge, Russ tilted Edge forward, lifting him from Honey’s still-hard cock and pushing him forward into Honey’s arms. Russ slammed into Edge from behind, rough and eager, trading the pleasure of toying with Edge’s breasts for the tight heat of pounding into his pussy, hands braced on his hips to maximum the force.

Honey, ever-playful, gently blew on Edge’s erect nipples, and Edge gulped and moaned against the phallic gag delightfully. Honey leaned forward, taking first one nipple then the other into his mouth sucking them until they were pulled taut and almost raw. He idly wondered what Edge’s milk would taste like and if the scarred skeleton would allow them to play with his tits after the babybones arrived.

Russ hilted hard inside of Edge, and soon his cum joined Honey’s. Russ didn’t pull out right away, worried that he might spill some of their precious seed. Instead he let Edge’s clenching pussy swallow it deep, the way Edge swallowed against the gag, making Honey’s cock dribble precum, ready for another round of fucking. They couldn’t forget their other lover though. Papyrus was waiting.

Russ carried Edge, bones still slick and damp from the shower, into the bedroom where Papyrus awaited them. Papyrus, always the thoughtful one, had lit some candles and made the bed with soft sheets and warm blankets.

“I called our jobs and let them know we’d be away for the weekend,” Papyrus said, eyelights raking Edge’s feminine form and drifting to his arousal and cum slicked pussy lips. “Let’s make it worth it, shall we?”

Papyrus took Edge from Russ and laid him reverently on the bed, then he positioned Edge’s legs onto his shoulders, checking to make sure Edge was comfortable before slowly entering him. Papyrus fucked Edge with intense focus, adding his cum to Edge’s already overflowing pussy before the three skeleton changed places and started the rotation again.

* * *

The four tall skeletons spent the entire weekend in sweet orgasmic ecstasy, only taking breaks from the pounding of Edge’s aching pussy for food, hydration, and, occasionally, to clean themselves up. The morning that they were all scheduled to return to work, Edge awoke to a trio of soullings glowing softly in his stomach where his lovers’ cum had so recently swirled.

He rolled over to wake them, only to realize that they were well and truly spent from breeding him constantly all weekend. He decided that he could wait a few more hours to show them their success.


	5. Day Four: Swapfellcest (Forniphilia, 69 Position, Orgasm Denial)

**Summary for the Chapter:**

> Pairing: Swapfellcest
> 
> Featured Kinks: Forniphilia, 69 Position, Orgasm Denial
> 
> Additional Warnings: Fontcest, bondage, tentacles, overstimulation, cock rings, blow job, facial

The plumage of the quill pen shimmied and swayed to the steady scratching rhythm of its ink-dipped tip. Blackberry filled out yet another menial report, inventory this time, that would never see the light of day again once he filed it. Still, the repetitive task gave him a sense of order and control without distracting him from his latest piece of… custom furniture.

“CHAIRS DON’T TALK,” Blackberry snapped, feeling his brother’s mouth move against the crotch of his unnecessarily short shorts. His magic had pooled in his pelvis as soon as he took his seat on his brother’s face, and the unexpected movement riled it up deliciously, a fact that Blackberry hid behind his scolding.

Whenever they played these types of bondage games, Mutt would deliberately misbehave in an attempt to make his brother lose patience and escalate the sexual portion of the game. Blackberry vowed not to be baited this time. Spreader bars placed at Mutt’s knees and elbows formed the structure of the improvised chair, and cuffs fastening his wrists to his knees and ankles to his elbows caused the lanky skeleton’s spine to arch in a lovely parody of pleasure. The leash attached to Mutt’s collar was wrapped securely around Blackberry’s gloved hand, keeping Mutt’s head raised for maximum sitting comfort. The vibrating cock ring around his desperate dark orange cock provided a pleasant counter-melody to the sound of Blackberry’s writing, and it wasn’t coming off until _Blackberry_ decided to take it off, no matter how much Mutt coerced him.

Mutt’s coercion intensified; Blackberry could feel the heat of his brother panting against his arousal-slicked folds even through the fabric of his shorts. Mutt’s tongue- the same deep orange as his throbbing cock- poked and prodded, finally slipping past the insubstantial fabric barrier and finding its way to Black’s plush pussy lips. Black shifted, preventing the tongue from questing any further, but the rapid scribbling of information on paper became jerky and discordant. He needed to focus.

Blackberry let his mind slip away to memories of other bondage configurations in which Mutt had become furniture. He envisioned the labor of carefully tying each knot so that it pulled just enough but not too much, a perfect balance of pain and pleasure. He remembered with titillating clarity how his brother looked contorted and forced to serve him. 

The first time they’d played this game, Mutt was positioned on the floor on his hands and knees with only a simple spreader bar holding his legs apart and handcuffs to keep him from touching himself. Blackberry had toyed with his living ottoman while pretending to read a book on the philosophy of war, idly rubbing his brother’s eager magic with the toe of his boot until Mutt begged him for release. Blackberry considered that occasion a decisive win for himself.

Their most recent session had gone quite differently though. Memories of Mutt with his arms tied above his head, legs bound tibias and fibulas to femurs which were in turn tied to Mutt’s ribcage did nothing to help Blackberry’s current situation. During that session, Blackberry had arranged candles along his brother’s ribs and pelvis with intentions to use him as a living candelabra, but the sight of firelight dancing across his brother’s pale bones like liquid sunset awoke an insatiable lust in him that he’d quenched in rough sex and hot candle wax. Blackberry had given in, and Mutt hadn’t done much more than summon his magic and let Blackberry melt from the flames of his desire.

This time, Blackberry refused to give in. Mutt may have sensed his resolve weakening, but two could play at the torment game. Setting aside his quill and paperwork, Blackberry removed one of his gloves, reached behind him, and very slowly stroked one sharp phalange up the length of Mutt’s engorged cock. “IF YOU’RE TIRING OF THE GAME,” he purred, “YOU ONLY NEED TO BEG FOR MY-” he emphasized the entendre of the next word carefully “- _MERCY_.”

Mercy did not appeal to Mutt; he wanted to antagonize his brother into a sexual frenzy. With a sly grin, hidden by his brother’s femurs, Mutt let his tongue split into three tentacles of magic. One tentacle wrapped around each of Blackberry’s femurs, spreading them apart until the third tentacle could wrap around the narrow strip of fabric covering his brother’s pussy and tear it away, exposing the glistening folds of Blackberry’s distinct royal purple magic. A wicked chuckle vibrated through the tentacles.

Blackberry barely had time to register the sound before the third tentacle plunged into his hot, wet pussy. Mutt wasted no time, curling his tongue and twisting it inside of his brother to reach his most sensitive spots. Blackberry’s eyelights rolled back as the intense pleasure blinded him. He stiffened, arching his spine, riding the thrusting tongue-tentacle for several long minutes; it took him that long to come back to his senses and remember that he was supposed to be the one in control. Pressure already gathered low in his pelvis. He wouldn’t last much longer; he needed to wrest control back from his orally talented brother and quickly. 

Mustering every bit of agility that he possessed from long years of leading the Underground’s Royal Guard, Blackberry managed to twist himself until he faced his brother’s thick, throbbing cock. Delicious tingles radiated from deep inside of his overfull pussy, so Blackberry didn’t bother with teasing either. Opening his mouth wide, he used his tongue to guide Mutt’s cock into his mouth and throat and began sucking hard, using his ungloved hand to stroke the base of the dark orange cock- total overkill.

Mutt gasped at the sudden sensation of having his cock deep-throated, licked, and jerked all at the same time. His ecto-magic was so sensitive already from the overstimulation of the vibrating cock ring that the pleasure was instantly unbearable, maddening, exquisite. The gasp pushed Blackberry over the edge. His pussy spasmed, clenching down on the tongue-tentacle and flooding Mutt’s mouth with a gush of hot cum. Blackberry moaned with Mutt’s cock still penetrating his throat, and Mutt sputtered a desperate “M’Lord” while lapping up his master’s juices.

That single word was enough. Blackberry slipped one sharp phalange tip under the edge of the cock ring and slashed it. The cock ring snapped free of the painfully pulsating shaft. Mutt cried out again, burying the tentacle into Blackberry’s tender cunt and his aching cock down his brother’s throat. After a split second delay, Mutt came hard.

Blackberry could barely swallow the massive load of hot, sticky cum that filled his mouth and throat. Panting, he released his brother’s cock from his mouth, still pumping energetically with his hand, allowing ropes of cum to spatter across his face until Mutt had fully emptied himself. 

Blackberry basked in the afterglow of his orgasm and ensuing facial, surveying the mess and mentally tallying points. This, he decided, would definitely be counted as a win. His mind already whirled with new ideas to try, new victories to achieve, and new heights of pleasure to attain.


	6. Day Five: Lamia Kustard (Size Difference, Distension, Knotting, Breathplay)

**Summary for the Chapter:**

> Pairing: Lamia UT!Sans x UF!Sans (Kustard)
> 
> Featured Kinks: Size Difference, Distension, Knotting, Breathplay
> 
> Additional Warnings: Monster heat, biting, cum inflation (slight), gaping, creampie

Sans didn’t know if it was the cold that awoke him or the intoxicating musky aroma circulating around his nest, but the skeleton lamia found himself wide awake and searching for the missing mate who had left them. Fortunately, his gold-fanged mate had also left behind a very distinct trail for him to follow.

Sans tracked Red’s scent with his forked tongue, savoring the flavor of the bigger lamia’s pheromones. Red must be in heat, a dominant heat if the scent was any indication. Sans’ magic tingled at the thought. Normally, he slithered lazily along, barely even keeping his torso off of the ground, but now he had to slither in a fully upright position to keep his sensitive cloaca from dragging along, likely leaving a trail of arousal in its wake.

Sans found his mate in a similar predicament- magic riled, desperate for stimulation, and reeking of dominant monster heat in the most delicious way. Red easily dwarfed him, and the gold-fanged lamia’s imposing size carried over to his double cocks as well. 

The bigger lamia was squeezing, stroking, and jerking on the dual shafts feverishly when Sans slithered up, mesmerized by the dripping precum at the tips and twin bulging knots at the bases. Sans’ magic fluttered at the thought of being filled by the huge cocks.

Red snapped to attention the moment Sans entered his field of vision. He tried to hide himself from his mate, ashamed of his lack of control, but Sans just gave a fang-filled grin and spread his cloaca, showing off his glistening arousal. He actually kind of liked it when Red lost control of himself in the throes of a dominant heat, though his mate feared injuring him. That’s why Red hid whenever his heat struck.

The sight of his tiny mate’s slick folds drove any thoughts of fleeing from Red’s mind. He pounced, easily pinning Sans to the ground. Sans moaned in anticipation as Red loomed over him, one skeletal arm on each side, boxing him in and smothering him in mouth-watering scent. Red maintained his control just enough to remember that his twin shafts couldn’t immediately be shoved into his mate. Instead, he started with one.

Without foreplay, Red relied on Sans’ natural lubrication and his own pre-cum to allow him inside that tight little pussy. The gold-fanged lamia thrusted deeply into his mate, and Sans arched his back, crying out as his pussy spread wide to accommodate the girth of one thick cock. The base of one knot pressed against him briefly before Red withdrew only to bury himself in that wet heat once more.

Red’s fierce thrusts rocked his mate’s entire body. The huge lamia nuzzled Sans’ neck, the only warning that the smaller lamia got before Red pulled up, lined up both heads of his double cocks, and plunged them deep inside of him. Sans’ stomach bulged; the cocks filled him from his cunt all the way to his ribcage. Each time Red moved inside of him, Sans felt the pleasure with his entire body.

Red sank his fangs into his mate’s shoulder, phalanges digging into the dirt to brace himself for powerful thrusts. Sans’ eyelights rolled back. He clung weakly to Red, succumbing completely to the pleasure of having his entire body railed hard by his frenzied mate. Instinct poured through Red, and his tail snaked forward, curling lightly around Sans’ neck. The smaller skeleton tried to focus on his mate’s hazy eyes, tried to nod to let him know that he accepted this form of sex play, but the tail snapped taut, cutting off his moans.

Sans gasped, moaned, and gagged in turns as Red’s tail tightened and loosened in rhythm with the forceful thrusting of the double cocks. Soon, the two knots, sticky with Sans’ dribbled juices, began to push at his pussy lips, begging for entrance. Sans’ forked tongue lolled, his phalanges dug into Red’s humerus, and his cloaca spread further, bit by bit until the knots entered him.

As soon as Red’s tail relaxed again, Sans cried out a delayed reaction to the shuddering orgasm that wracked his body. His pussy clenched around the two cocks, squeezing them and pressing against the knots. Red roared, throwing back his head. He came hard, knots emptying into the sweet little pussy convulsing around them. Red bucked a few more times while his mate’s hungry cunt swallowed up every drop of his thick, hot cum.

Sans’ stomach swelled, and his pussy spasmed as orgasm followed orgasm. He loved those pulsing cocks inside of him. He loved receiving Red’s cum, the way it filled him, the way it mixed with his juices and gushed from his gaping cloaca when Red pulled out, the way the deep red color swirled in his still-full stomach and stained his entire lower body.

Knowing that Sans’ body would be battered and exhausted after such an intense and through fucking, Red pulled his tiny mate close and curled around him. Together, the two lamias slept out under the stars, fully satisfied… for now.


	7. Day Six: Classic Fontcest (Domesticity, Upskirt Sex, Creampie, Bulges)

**Summary for the Chapter:**

> Pairing: UT!Sans x UT!Papyrus (Classic fontcest)
> 
> Featured Kinks: Domesticity, Upskirt Sex, Creampie, Bulges
> 
> Additional Warnings: Spanking, Grinding

Sans really loved it when Papyrus cooked, despite the fact that most of the recipes that Papyrus knew had been taught to him by Undyne and were completely inedible. It wasn’t the promise of a delicious meal that drew Sans to the kitchen time after time when Papyrus started pummeling ingredients, oh no. Sans could easily resist the draw of dismal meals, but he couldn’t stay away from the sight of his brother in an apron. It helped that Papyrus liked to wear only the apron and nothing else.

Today, though, Papyrus had switched things up, and Sans had to say that he approved. He peered into the kitchen from the doorway, taking in the view with hungry eyelights. Papyrus wore his apron, as usual, and a short ruffled skirt that showed off a pair of clingy panties. Sans could feel his magic springing to life in his pelvis, so he crept into the kitchen to see if he could score a sweet treat before dinnertime. 

Papyrus glanced as his brother sneaking into the kitchen. His skirt ploy seemed to be working! The tall skeleton made quite a show of bending over to check the oven. He always kept his ecto-body summoned while he cooked, but it had nothing to do with cuisine and everything to do with providing an irresistible lure for his brother. Sans couldn’t resist the siren song of supple orange ecto-flesh, and Papyrus took full advantage of it.

Sans stepped up behind Papyrus, using a nearby stepstool to enhance his height, and rested one hand on each of his brother’s hips. Suddenly, he yanked Papyrus backwards until his ass brushed against the front of Sans’ basketball shorts. Papyrus could feel his brother’s erection through the fabric of both the shorts and his panties, and he liked it. Sans must’ve liked it too because he began to grind against Papyrus, running the length of his cock, still in his pants, against the generous curve of his brother’s ass.

Papyrus tilted his hips, and the clothed length slipped between his legs. Sans rocked his hips, grinding faster against the sensation of heat from Papyrus’ pussy. Papyrus moaned softly when his brother’s erection caught on his clit, sending a shiver of pleasure through him. Sans moaned, louder than his brother, in return. Pre-cum soon darkened the front of his shorts, and arousal seeped from Papyrus’ panties to glisten on his thighs. The panties were tight enough to show the outline of Papyrus’ puffy pussy lips, and they clung wetly to his inner folds.

Reaching behind him, Papyrus stroked at the bulge in his brother’s pants. Sans leaned close to his ear canal and growled in a very sexy voice: “don’t stop cooking.”

Curious, Papyrus obeyed. A few seconds later, Sans’ fingers slipped under the hem of his panties, tugging them down. Papyrus tried to concentrate on stirring his pasta sauce, but his brother’s fingers returned to the scene of the panty removal and began to knead at his folds, gently spreading them apart until his fingertips circled his brother’s dribbling fuckhole. Papyrus heard the sound of fabric hitting the kitchen floor a split second before the tip of his brother’s cock pressed at his pussy entrance.

Papyrus gasped and dropped his spoon into the sauce. Sans pushed into him, groaning in pleasure. “you dropped your spoon,” he murmured against his brother’s skull before lowering his head to kiss and suckle at the vertebrae of his brother’s neck. Papyrus fumbled to retrieve the spoon only to drop it again because Sans plunged deeply into his pussy, his cock stroking Papyrus’ insides and flooding his body with pleasure.

“I NEED… TO STIR...THE SAUCE,” Papyrus protested in a weak stammer. Sans’ hands settled on his hips again, clinging to the skirt fabric and the iliac crests beneath. The full skirt bounced and swayed with the force of the short skeleton’s thrusts.

“don’t. let. me. stop. you.” Sans huffed, punctuating each word with another powerful buck of his hips.

With a herculean effort, Papyrus concentrated enough to drop the pasta into the water, but a hearty slap on the ass from his brother caused his drop some of it onto the stove where the flames of the cooktop charred it. “THE PASTA,” Papyrus moaned, losing focus. “I… AH… AHHHH… MMMM.”

Sans’ savage thrusting hammered his brother’s pussy. The underside of Sans’ cock rubbed deliciously against Papyrus’ sensitive spots, and the length of his cock filled the summoned magic completely. Giving up on any semblance of completing the meal, Papyrus gripped the stove with both hands, bracing himself against the ruthless fucking and mewling for more.

His brother’s fingers dug into his hipbones, and Papyrus screamed in pleasure a moment before Sans bottomed out in his pussy, groaned, and came. The hot cum and pulsating cock pushed Papyrus over the edge as well. His pussy tightened, locking around his brother’s cock and milking every bit of cum from his thick shaft.

When Sans finally pulled out, his magic, mingled with Papyrus’ juices, bubbled out of the tall skeleton’s gaping pussy. Sans reached out and spread his brother’s fluttering cunt a bit wider, watching as aftershocks from the orgasm made sticky strands of cum flow out of it onto his brother's thighs and drip onto the floor. 

“since you handled dinner,” Sans purred, “i decided to do a little cream pie as dessert.” Sans used a finger to scoop up some of his cum. He held it up to Papyrus’ mouth. “wanna taste?”

Papyrus drew his brother’s finger into his mouth with his tongue, swirling his tongue around it and sucking it in a very suggestive manner. Sans’ sockets grew hazy with desire again, but Papyrus stood up suddenly, pulled his panties back up, and began to plate his poorly-stirred sauce and oddly both raw and overcooked spaghetti. When Papyrus put the two plates of supposed food on the table, Sans sighed.

“DINNER WOULD BE MORE PALATABLE IF YOU STOPPED SABOTAGING MY CULINARY MASTERPIECES WITH YOUR LIBIDO,” Papyrus commented drily.

Sans picked up a mushy noodle with an uncooked end and a scorch mark on it and tossed it into his mouth. “i could stop,” he offered.

Papyrus laughed and waved away his brother’s words. “UNLIKELY. DINNER TOGETHER AGAIN TOMORROW?”

“what are we having?”

“SPAGHETTI AND FACIALS. NYEH HEH HEH.”


	8. Day Seven: SpicyKustard (Spit-Roast, Socket Penetration, Begging)

**Summary for the Chapter:**

> Pairing: UT!Sans x Fellbros (SpicyKustard)
> 
> Featured Kinks: Spit-Roast, Socket Penetration, Begging
> 
> Additional Warnings: Heat Cycle, Blow Job, Face Fucking, Rough Sex, Deep-Throating, Dirty Talk, Gaping

When your skeleton boyfriend shows up at your house in the throes of a submissive monster heat, begging to be fucked, there isn’t much of an option except to give him what he wants. Red and Edge weren’t the kind of skeletons to let their shared boyfriend suffer, not when there was plenty of pleasure to be had by all. Nearly dragging him into the house in their enthusiasm, the two skeletons had Sans stripped naked on his hands and knees on their living room floor in a matter of seconds.

The fun began at a furious pace, but nothing seemed to satisfy the sexual desperation that burned through Sans’ bones and magic.

“please… fuck me harder… destroy my slutty little pussy… please!” whimpered Sans, rubbing his clit and fingering his already battered pussy while Red savagely pounded his asshole. Edge’s sharp phalanges scraped Sans skull; between the pleas and whimpers, Edge throat-fucked the smaller skeleton, pulling out and then snapping his hips forward to plunge the thick length of his spiked cock deep into the needy skeleton’s throat. Sans’ tongue slid against the underside of Edge’s cock, and his moans vibrated through the deep red shaft until Edge and Red, with twin groans of release, poured more of their cum into Sans’ greedy holes.

The two Fell skeletons breathed heavily, discussing the idea of switching places again to keep up their momentum while Sans squirmed between them, eager for anything to fill him up.

“make me your fucktoy… your cocksleeve… your cum dumpster… anything, just don’t stop!” he begged feverishly.

Edge lifted Sans’ chin, inspecting the cum and drool dribbling out of his boyfriend’s mouth with every word. Red surveyed Sans from the back, taking in the gaping pussy and asshole, both looking bruised, twitching, and leaking a mix of cum and Sans’ juices. They wanted to alleviate their boyfriend’s heat cycle, but they also didn’t want to hurt or permanently damage him.

“I THINK YOU MAY NEED A BREAK,” ventured Edge kindly.

“yer fuckholes are pretty wrecked,” pointed out Red.

“i don’t care,” wailed Sans. “i need more… please. make me cum until i dust.”

“hey now, we don’t want to go that far,” said Red. “but your mouth, ass, and pussy can’t take much more punishment.”

Edge regarded Sans in pensive silence for a moment. “THERE ARE… _OTHER HOLES_ THAT WE COULD FUCK, YOU KNOW,” he said slowly.

“anything,” pleaded Sans.

Edge lined up his cock with Sans' face, but instead of using it to pry the other skeleton’s mouth open for more deep-throating, he circled Sans’ eye sockets with it, spreading the short skeleton’s saliva and a bit of dark red cum around the edge of it. Sans moaned, loud and low, and, taking that as consent, Edge thrust his spiked cock into his boyfriend’s skull with a lusty sigh. The bottom of Sans’ socket dragged along his entire throbbing length, and he loved the way the inside of the bare skull bones felt against his sensitive magic.

“so what am i supposed to do?” complained Red, still hard and hoping for something hot and tight to put his own cock into.

“HE HAS _TWO_ SOCKETS.”


	9. Day Eight: CherryBerry (Jealousy/Possessiveness, Solo/Masturbation)

**Summary for the Chapter:**

> Pairing: US!Sans x UF!Sans (CherryBerry)
> 
> Featured Kinks: Jealousy/Possessiveness, Solo/Masturbation
> 
> Additional Warnings: Exhibitionism, Public Sex, Mutual Masturbation

Nobody ever expected Blueberry to be the jealous or possessive type. Most monsters took one look at Blue and saw nothing except sweetness and innocence with no possibility for anything darker hiding beneath the surface. Blue definitely wasn’t cruel, and he certainly wasn’t unkind. He just possessed an ever-so-slight jealous streak, and sometimes he needed to remind his boyfriend, Red, who he belonged to.

The two skeletons sat together in a monster-run restaurant, one that thankfully served food that wasn’t too greasy (for Blue) or too healthy (for Red). The couple frequently struggled to agree on dining options, so this outing was supposed to be a rare treat for them. Unfortunately, a waitress showed up shortly after they’d been seated and ruined everything before they could even finish choosing items off of the menu.

The buxom rabbit monster sidled up to Red and put a far too friendly hand on his shoulder. “What can I get you, handsome,” she asked with a flirtatious giggle. Red smiled widely, his gold tooth glittering in the pleasantly muted light.

The soft roundness of Blue’s face didn’t wear frowns well, and the glare from his baby blue eyes was less than intimidating, but Red knew what was coming. He shrugged off the rabbit monster’s hand a second too late. There would be no stopping Blue now… and Red kind of liked it.

“THAT’S MY BOYFRIEND YOU’RE GROPING,” Blue snapped sullenly at the waitress. 

She backtracked, trying to calm Blue down. “Sorry, I didn’t mean to-” Blue wasn’t done speaking though, and he talked right over her apologies.

“HE’S MINE,” Blue repeated, staring the rabbit monster directly in the eyes. He grabbed Red’s collar and used it to drag his boyfriend halfway across the table towards him. Their teeth came together with the sharp CLACK of a rough skeleton kiss, and Blue’s tongue forced its way inside of Red’s mouth. When Blue finally released him, Red was too stunned and aroused to move back into his own seat.

“ALL OF HIM IS MINE,” growled the possessive skeleton, standing up from his seat. He threw down onto the table skillfully- thanks to his training from Alphys, who likely had not intended it for such a use. Blue then grabbed Red’s basketball shorts, and without warning, yanked them off, leaving Red’s pelvis exposed to anyone who cared to look, including the rabbit monster, who blushed deeply and averted her eyes.

Blueberry reached forward and stroked Red’s sensitive pelvic symphysis. Red gasped, and magic pooled in his pelvis, coaxed to life by his boyfriend’s skilled hands. Red tried to cover his pussy as it formed, but Blue shoved his hands away. “SEE THIS? IT’S ALL MINE.” The way Blue growled his words made Red shiver, and his delicate folds soon glistened with arousal.

Blue noticed immediately. With a devious grin, he used two fingers to spread Red’s folds, showing off his fluttering pussy to the entire restaurant, watching more arousal dribble out of it and onto the table. “TELL THEM WHO YOU BELONG TO, RED,” Blue ordered.

“you- OOH… aaaaaah!” Red had barely spoken when Blue trailed one phalange lightly across his fuckhole then gently caressed his clit. Red’s spine arched in pleasure, but Blue withdrew his hand, much to Red’s disappointment.

“THAT’S RIGHT, AND NOW I’M GOING TO MARK WHAT’S MINE SO THAT EVERYONE HERE KNOWS IT!” With those words, Blue tugged his trousers down, revealing that he had gone commando for their date and that his riled up magic had formed a thick, throbbing cock ready to pound his boyfriend into oblivion… except Blue had different plans. 

“TOUCH YOURSELF,” Blue demanded, following his own instructions by wrapping a gloved hand around the base of his cock. Red obediently dipped two phalanges into his soaking pussy, watching Blue with lust-filled eyelights.

Blue’s grip tightened at the sight. He squeezed his shaft and began to move his hand slowly up and down the length of it. Precum beaded at the tip and slowly dripped down to join Red’s arousal on the tabletop. The bunny waitress had fled, but at that point, Blue no longer cared. He only cared about making Red his, right then and there on the restaurant table. 

Red’s fingers slid in and out of his pussy, and Blue’s hand moved up and down on his cock. The pair of skeletons increased their rhythm, eyelights locked, blocking out the world, silent with shock, around them. Blue huffed and growled, and Red responded with lewd moans, filling that silence with the music of sexual gratification. Blue could feel his orgasm building, so he reached down and gave Red’s clit a swift rub and a slight pinch.

Red stiffened and came, squirting fluids onto the already sullied table. The sudden, powerful orgasm made Red scream in pleasure, and the sound brought Blue to the edge with him. With one last stroke, Blue came too. He angled his cock so that the thick ropes of cum spattered across Red’s pussy and thighs, a bright blue reminder of who owned that tight little cunt.

Unsatisfied with only a single orgasm, Blue actually climbed up onto the table, lining up his still pulsing cock with Red’s eager pussy to claim him again. He never got a chance to slip into the warm embrace of his boyfriend’s insides though because a hand made of purple flames collared him. A matching hand snatched Red by the ankle, and both skeletons were unceremoniously tossed out of the restaurant, pants still around their respective ankles.

Blue puffed out his cheeks in irritation. “IT’S SO HARD TO FIND GOOD RESTAURANTS IN THIS TOWN!” he complained.

Red chuckled from his prone position on the sidewalk. “it might be because we keep getting kicked out of all of ‘em…”


	10. Day Nine: Kustard (Praise Kink, Heat Cycle)

**Summary for the Chapter:**

> Pairing: UT!Sans x UF!Sans (Kustard)
> 
> Featured Kinks: Praise Kink, Heat Cycle
> 
> Additional Warnings: Size Difference, Oral Sex, Gaping, Creampie, Snuggles

“this isn’t revenge for the socket-fucking thing, is it?” asked Red with a nervous laugh. During his dominant heats, Sans sometimes got larger, and this heat cycle he absolutely dwarfed Red, indicating a particularly strong heat.

Sans just grinned, fixing his hungry eyelights on Red’s naked bones. Red shuddered as his magic gathered in his pelvis to form a delicate pussy. Sans slid his basketball shorts down, the influx of magic from his heat cycle making his cock longer and thicker than normal. Red couldn’t hold back a moan. Sans was going to destroy him, and he wanted it badly.

“revenge sounds so negative. consider it repayment for the pleasure and satisfaction you gave me during my last heat,” Sans growled softly, pushing Red down onto his back and looming over him in a way that made Red shiver in anticipation. “i’m going to make you feel so good.”

Planting a kiss on Red’s mouth, Sans then backed up until his skull rested between Red’s femurs. He breathed in the heady scent of his boyfriend’s arousal, and it made his cock twitch. Oh how he wanted to wreck that pretty pussy until Red fainted from the overwhelming pleasure, but he didn’t want to hurt the much smaller skeleton. Opening his jaws to reveal fangs (another side effect of his extreme dominant heat), he dipped his tongue teasingly into Red’s silky folds.

Red squirmed. “don’t tease,” he whimpered. 

Sans chuckled. Bracing his larger-than-usual hands on Red’s greater trochanters, he wrapped them around the joints of Red’s hips and opened his legs. His thumbs slid up Red’s slit then parted his pussy lips, revealing the glistening opening. With a rumbling hum of approval, Sans sank his tongue into Red’s tight little hole. Even his tongue barely fit, filling Red and stretching him out as it delved deeply into his pussy.

Red moaned again, digging his phalanges into the blankets beneath him. Withdrawing his tongue, Sans chuckled again, his breath hot on Red’s slick opening. “better?” he asked, not waiting for an answer before burying his tongue back in that sweet, delicious cunt. He hummed and groaned as he swirled his tongue inside of Red, letting the vibrations from the sounds stimulate his boyfriend’s insides.

Spine arching, hips lifting, Red uttered a litany of “yes”s and “more”s to the rhythm of Sans’ talented tongue. The way his huge boyfriend’s nasal ridge rubbed against his clit drove him wild, and Sans was just getting started. Red knew he wouldn’t last long at this rate.

As soon as Sans felt Red’s pussy tightening, he withdrew his tongue again, admiring the way he’d stretched Red’s hot, wet fuckhole with only a few minutes of gentle tongue-fucking. He licked the arousal from around his mouth, then lifted himself up to nuzzle and nibble at Red’s neck. The scrape of fangs made Red shiver, and his body ached from the orgasm that he hadn’t released yet.

“you’re delicious,” murmured Sans against Red’s clavicle. Sans’ thumb found Red’s clit and began to stroke and press it. “now cum for me, baby. cum for me and scream, just the way i like it.” His thumb made quick movements on Red’s clit, and the sweet release of the orgasm was so intense that Red’s hips lifted entirely off of the bed.

Red screamed as his pussy clenched and fluids gushed out of him. His body trembled with pleasure as Sans thumb coaxed another orgasm out of him just by playing with his clit.

“mmm,” rumbled Sans. “i love those sounds you make, so desperate and horny. i can’t wait to slip my cock into your tight little cunt.”

“yes… yes,” mewled Red, his voice making Sans’ white eyelights go hazy with arousal. Nothing fed a dominant heat like a willing submissive partner, especially one who asked for sex so adorably.

“so cute,” purred Sans, pressing his enlarged cock against Red’s opening, rubbing his precum into Red’s fluids for added lubrication. Red covered his face with both hands to hide his blush, but Sans brushed the hands aside with one of his own. “let me see you, baby. i love your blush, and i want to see you come undone when i’m fucking you.”

Everyone who met him, humans and monsters alike, viewed Red as a slut because of the universe he came from (“you know how those Underfell monsters are…”), the collar he wore (“in public!”), and the lewd jokes and gestures that he made (causing those who encountered him to avert their eyes and shake their heads), but nothing turned Red on more than some good old-fashioned praise. He flustered easily at the slightest compliment, and Sans took full advantage of it.

There would be no slipping the huge shaft into Red’s pussy; penetration was a delicious game of inches. Once Sans got the head of his cock in, he had to pull back and thrust just to get a little further in each time. Red loved the overfull feeling and the way his pussy stretched almost beyond its limits to accommodate the girthy member. Each tiny thrust, each slightly deeper entry rubbed along his sensitive insides and made him gasp.

“you’re so… fucking tight…” groaned Sans. “it feels amazing. i can’t believe you’re taking it all so well.” Sans kissed along Red’s jawline as one final buck of his hips buried him to the hilt inside of his boyfriend. Red let out a yelp, then began to pant as his pussy spasmed around the too-large cock filling it.

“please… start moving,” begged Red breathlessly, craving the complete and utter destruction that Sans’ cock would cause.

“anything for you,” Sans murmured into the curve of Red’s neck.He began to rock his hips slowly, withdrawing a little then sliding back in with gentle, smooth motions to make sure that Red had plenty of time to adjust to his length and girth. He wanted to slam into that tight, clenching heat, but he paced himself. 

Red let out mewling cries each time the massive cock moved inside of him. Every single nerve in his ecto blazed with sensitivity, and even the light friction sent waves of pleasure through his entire body. When Sans sped up his thrusts, Red saw stars. His eyelights morphed into lust-fogged hearts, and his tongue flopped from his open mouth. He couldn’t hold back his desperate, pleading moans, and every bit of his reaction spurred Sans on to greater efforts.

“you’re gripping me… so tightly… it’s so good… fuck you’re so sexy,” Sans snapped his hips in rhythm with his words. “your hot little pussy… the curve of your bones…” Sans traced a phalange along the underside of one of Red’s ribs, making his boyfriend nearly cum right then and there. “the sounds you make… your expressions… everything about you… is so perfect… so beautiful… and all mine.”

Red’s pussy clamped down on Sans’ cock, but Sans just kept pounding away through his boyfriend’s orgasm. With fit no longer an issue, Sans slammed into Red over and over again with powerful thrusts, rocking the smaller skeleton’s entire body. Red tensed and came again, and still Sans refused to stop. Red’s moans became wordless screams of overwhelming pleasure.

“you’re doing so well… and i’m so close… i’m… oh fuck, Red… i’m gonna… gonna…. aaaah!” Sans buried his cock in Red’s pussy one last time. A shudder traveled down his spine, and his cock throbbed. Pleasure exploded in Sans’ magic, forcing Red’s magic to respond. The two skeletons shared the last orgasm, Red’s pussy clenching and releasing Sans’ pulsing shaft as it poured hot sticky cum inside of him.

Red’s greedy cunt drank down more and more of Sans’ thick load as the big skeleton moaned at the glorious sensation of his boyfriend’s pussy milking the cum from him. Breathing heavily, Sans pulled out, watching blue cum and Red’s own fluids spill out of his gaping hole and onto the blankets. “now that’s a beautiful mess,” he commented. “it’s no skull full of cum, but i suppose we’re even.” Sans used one thumb to brush Red’s wide-open pussy for a better viewpoint, and more blue cum bubbled out of the fluttering entrance. _Gorgeous._

“i dunno,” countered Red, “it might take another session… or five.” He disliked the emptiness that Sans’ massive shaft left behind in its absence, but the adulation on his boyfriend’s face as he observed his handiwork made up for it.

“i love you, Red,” said Sans with an indulgent grin, leaning down to give his exhausted boyfriend a skeleton kiss on the forehead only to discover that Red had already dozed off.

Thankfully, curling one’s entire body protectively around one’s much smaller (and cum-filled) boyfriend also fed a dominant heat.


End file.
